I tried specifying the file directly in the XML and with an M3U but neither worked.

Sidenote: before the "Exiting" text, I saw what appeared to be reltime playback status, which would figure given the switches I was specifying, but it stuck at 0m00s before timing out.

I assumed it'd be able to handle MP2, is this not so? I've done loads of Googling and I know it'd be easy to transcode and stream, but I'm deliberately trying to live stream (not fileserve) bit-accurate to the original source.

Ah, I'd never considered trying with ffmpeg! I'll give it a shot and see what happens.

Back when I used a Psion Wavefinder to listen to DAB, the DABBar third party control software had an integrated streaming server which exposed each PID as a .mp2 URL and streamed them live without transcoding. Winamp 2 handled it just fine, so I have high hopes for VLC and Foobar..._________________.

I upgraded to avconv 11.2, and it still gives me the same error. There's something odd going on. (It's a valid MP2, VLC has no problem playing or even copying the ES to a new MP2 which has the same filesize). Time to make some more MP2 test files!_________________.

Forcing the MP2 format got me further, but it seemed initially to bomb immediately after starting to stream. But after that, it began to work, as long as I used the force format flag. Unfortunately though neither VLC nor Foobar begin to play the stream.

In general having a "file extension" on your mountpoint is useful as there are still many broken players out there.
The alternative is probably to force output format by adding "-f mp2" right before icecast://_________________I maintain the Icecast project. If you want to show your appreciation.